Outboard motor with fluid clutch



Feb. 2o, 1951 D, KLQSS 2,542,682

OUTBOARD MOTOR WITH FLUID CLUTCH Filed Feb. 9, 1950 3 SheetS-Sheel'l 1 Feb. 20, 1951 D. D. KLOSS OUTBOARD MOTOR WITH FLUID CLUTCH Filed Feb. 9; 1950 Feb. zo, 1951 D, D; KLQSS 2,542,682

OUTBOARD MOTOR WITH FLU-IDy CLUTGH Filed Feb. 9, 1950 3 She'SI-Shee'b 5 W lv 25 35 30 65 7 86 W SZ 70- ZZJH `L ik I /IV 90 Patentecl Feb. 20, 1951 UNITED STATES OUTBOARD MOTOR WITH FLUID GLU'ECH Dale D.. Kloss. Minneapolis.. assis-.ooo ioy Chamrion Motors CilxlfloaayiY15WhtoitA Minn., a corporation of Minnesota,c

Application February 9, 1950K,- SerialvNo. 143,280-l (Cl-. li-179 This invention relates to outboard marine motors and more particularly to improvedzpower transmission mechanisms for such motors.

Among the important objectives of the invention is the provision of an outboard motor prof viding greatly improved maneuverability-of boats equipped therewith and, generally, having greater overall utility than conventional motors.

Another object of the invention is the provision of an improved variable speed drive for outboard marine motors.

A further object of thev invention is the` pro,- vision of an improved power transmission or drive mechanism for outboard motors providing neutral drive and variable speed drive.

A further object of the invention is the-provision, in an outboard motor, Vof an vimproved variable speed power transmission mechanism of the type wherein variable speed drive is achieved by a slippage clutch. As is. `.well known, lthe achieving of variable torque transfer or speed drive by means of slippage clutches is accom,- panied Iby generation of `heat which must vbellissipated at a satisfactory rate to prevent overheating and damage to theparts. VThe instant invention is, therefore, directed toward the proaisgion of van improved drive for outboard motors involving a slippage clutch for the purpose of obtaining variable speed drive,'and wherein heatgenerated by the slippage clutch is dissipated -to the rwater in which thekpropeller of the motor issubmerged at a sunicient rate to insure cool oper-ation .of the mechanism. To this end, the slippage clutch of the power transmission-mechanism'is Acontained within a cavity of the -normallysubmerged portion of the housing Vstructure of -the motor, and is submerged or largely submerged in iluid c ontained within said cavity, and through which fluid and housing structure the heat generated by the `slippage clutch is rapidly dissipated to the body of water in which the said `portion .ofthe housing structure of the motor is normally submerged.

Another still further object of the invention` is the provision, in an outboard motor, .of kan improved variable speed drive involvinga `fluid coupled torque transfer unit.

Still another object of the invention is the provision, in an outboard motor, offan .improved fluid drive including an improved variable slippage fluidrclutch. y

An important feature of .the invention is the provision, in an outboard motor, -of a variable variable slippage clutch, friction brake and controlomeansgtherefor, DIOl/:diilgi IYlRI'Ql/ed, 69.1315191 of the variable torque transfo! factor of" 'the slippage clutch.

As another important feature of the invention, I` providel` in an. outboard motor struotoro, o variable speed driveinvolving-aunique combination of. variable slippage clutch and positiveacting clutch meansv for lockingY the relatively rotary elements of the slippage clutchv against rotation.

A S a further. feature of the invention, Il oro; vide, in an outboard motor structure, aV unique combination of variableslippage clutch, positiver acting- Lclutch, f or lock-ing the friction clutch elements. oeoiootslipoogo, a Vfriotioo broke, vand common control mechanism Afor the slippage clutch, positive-actingelution,Y and friction brake.

The. abovev and other highlyr important objects, advantages and important lfeatures Y of the invention Willbe madelfiurther apparent -from the following specification, claims fand appended drawings. i'

VIn the accompanying drawings,A like characters `indicate `like parts throughout the several views.

Referring. -to'tho drowllgo Fig; -1 a view iii-side elevation, with some ApartsY broken away Aand ,some parts shown in sec# tion, ofY an outboard marine motor Aincorporating a prefer-red embodirnhent of theinvention; Y

Fig. 2` is a greatly enlarged fragmentary Sooviow, with somo parts brokn away and some parts shown in axial section of the lower normally submerged portion of the motor structure of Fig; 1;;

Fig. Blisavperspectiveviewon thescale of Fig. 2 of a propeller-shaft shown in section in Fig. V2.;

4 Ais a detail perspective Viewl on the scale of-Eig 2 of the front Wall portion of a .fluidldr'ive unitor clutch shown insection infFlig. :2f

Fig. 5 is a detailed f.ragfrnentary.secty nal View lon the scale of Fig. Zand takerrlolziheline 5-5 Iof Eig- 2;

Fig. 6r is a detailed sectional View on a still furtherV enlarged scale, .taken on the line 6.--3

of-Fig. v2;

Fig. 7 is a fragmentary detail sectional view, taken on the. line 1f] of Fig. 6; and f Fig. 8 is a .detailsectional view taken on the In thedrawingathe invention is illustrated in conjunction with an otherwise standard commercial type1 of, outboard marine motor involving tti@ .oSoal-.roWor-,oooa ioolioatod.asaoootroty by ,the nowo. .of o. voonvorlborlol internal .Qomlouo- 3 tion engine involving the usual pull starter knob 2 and combined throttle and spark control lever 3. Depending from the power head I is a hollow drive shaft housing structure 4 involving a normally submerged unit or portion 5 that is detachably secured to the lower part of the housing structure 4 by stud screws or bolts 6 or the like. The motor structure illustrated is provided with conventional clamping means l (see Fig. 1) for detachably anchoring the outboard motor to the transom of a boat, not shown. The clamping means 'I is anchored to the upper portion of the depending housing structure 4 by means of a suitable bearing collar 8 (see Fig. 1) surrounding the upper cylindrical portion of the housing structure 4 and in which the said portion of the housing structure 4 is vertically journalled for pivotal steering movements of the power head I and depending housing structure 4 and 5. For the purpose of imparting pivotal steering movements to the motor in the bearing collar 8, there is provided the customary steering bar or arm 9.

Extending downwardly from the power head through the depending housing structure 4 and into the lower unit 5 thereof is a vertically disposed drive shaft I@ (see Figs. 1 and 2), that is suitably journalled in the upper and intermediate portions of housing structure 4. This drive shaft l5 is driven from the power head and may be assumed to be directly and conventionally vcoupled to the crank shaft thereof, not shown. The intermediate portion of drive shaft I3 is journalled in a suitable bearing II withinhousing structure 4, and the lower end thereof is journalled within the lower unit 5 of the housing structure, by means of sleeve bearings I2 and I3, lall as best shown in Fig. l.

The motor structure illustrated is provided with a conventional marine propeller I4 that is mounted on the rearwardly projecting end of a propeller shaft I5 and to which the said propeller is connected for common rotation by means of the usual shear pin IB (see Fig. 2). The propeller shaft I5 is journalled in the lower housing unit 5 by bearing means comprising a ball bearing set il', and the inner end portion of said shaft I5 is contained within a large cavity I8 within the normally submerged housing unit 5.

As a feature of the invention, I provide, for coupling the lower end of drive shaft I5 to the propeller shaft I5, power transmission mechanism contained within cavity I8, and immediately to be described. In accordance with the preferred embodiment of the invention illustrated, this power transmission mechanism comprises intermeshing bevel gears I9 and 28, and a fluid drive unit or slippage clutch, indicated as an entirety by ZI (see Fig. 2). The bevel gear I9 is mounted fast on the lower end of drive shaft Il), and its companion gear 2B is mounted fast on an elongated rearwardly extended tubular hub 22 of the front wall 23 of the outer shell or casing of vthe fluid drive unit or slippage clutch 2I (see Fig. 2) Preferably, and as shown, the bevel gear 2B is screw-threaded on the hub 22 and tightly against the front wall 23, as shown at 24 in Fig. 2. The said outer shell or housing structure of the fluid drive unit 2l further comprises a rear end wall 25 axially spaced from the front end wall 23, and an intermediate generaly annular p..- ripheral wall 23 to which the end walls 23 and 25 are securely anchored by screws or the like 21 in a manner to provide a fluid-tight cell between the interior of the shell or housing structure 2l and the cavity I8. By reference particularly to asfiacsz Figs. 2, r1 and 8 it will be seen that the shell or casing structure 2l is journalled in the normallysubmerged unit or portion 5 of the housing structure 4, concentrically of the propeller shaft I5, by means of a stationary sleeve bearing 28 having circumferentially-'spaced axially-extended oil channels 29 in its inner surface. The sleeve bearing 28 may be assumed to be press-fit into a receiving bore in the lower housing unit 5.

The fluid drive unit or clutch ilustrated is structurally closely analogous to certain fluid pumps and further comprises an inner body element or rotor 30 mounted fast on the propeller shaft I5 b y means of spline keys 3I on the intermediate portion of propeller shaft I5. This inner body element or rotor 3l), which in its broader aspects is closely analogous to conventional pump rotors, is formed with a circumferentially-spaced plurality of radially outwardly opening vane channels 32, one of which is tted with a sliding vane 33, and the others of which are equipped with similar sliding vanes 34 (see particularly Figs. 2, 5 and 8). For reasons hereinafter clarified, the sliding vane 33 is subject to the outward yielding biasing action of a coil compression spring 35, shown best in Figs. 2 and 5.

In accordance with more or less conventional pump practice, the interior surface of the rotary peripheral wall 23 of the fluid drive unit is made generally elliptical in transverse section to provide therebetween and the circular periphery of the rotor 3!) diametrically-opposed generally crescent-shaped chambers 36 and 3l, shown best in Figs. 5 and 6. Of course, under normal operating conditions, the sliding vanes 33 and 34 make sealing engagement with the generally elliptical inner surface of the peripheral wall member 28 and move inwardly and outwardly once for each 360 of relative rotation between the rotor-acting inner body element 30 and the rotary outer body element or shell 26. In the preferred embodiment of the invention illustrated, the entire open space within the cavity I8 is filled with a suitable coupling fluid, preferably oil, which serves also as a lubricating medium for the mechanisms within cavity I8, and further as a heat-conducting medi- Also in the preferred embodiment of the invention illustrated, and preferably, the cavity IB is lsupplied with oil by gravity action from an annular reservoir-acting cavity 33, also located in the housing unit 5, but above the cavity I8 (see Figs. l and 2). The reservoir-acting cavity 38 is concentric with the drive shaft IG and communicates with the cavity I8 by one or more fluid passages 39, shown best in Fig. 2.

The inner end of the propeller shaft I5 extends into the elongated hub 22 and is journalled therein through the medium of a sleeve bearing 39', shown best in Figs. 2, 7 and 8, and the projected end portion of hub 22 extends into and is directly journalled in a bore 4I! in a water pump housing body 4I (see Fig. 2) This water pump housing body 4I closes the front end of the cavity I8. The water pump housing 4I, along with mechanism contained within the cavity I3, is removable through the forwardly opening housing bore 42, but is normally held in placefby a laterally displaceable section 43 of the lower housing unit 5 (see Fig. 2). By further reference to Fig. 2, it will be seen that the laterally-displaceable section 43 has interlocking tongue and groove connection with the housing unit 5 at 44, and that said displaceable section 43 is normally locked against lateral displacement by means of 'a spring-pressed locking pin 45, which is accessible A"fori" forced retraction through-ia gf'sriiall boreti.-

Therwater pump is ofl the centrifugal`v impeller type andthe housing 4I vthereof defines the forf wardlyv opening cylindrical-'pump cavity'l, the

open'front end of which is--norm`allyfclosedbyf-f` a cover Vplate decu-t-A awayorotherwise. formed-l to provide at its bottom portion-a Water intake port [I9 land at its-upper portion-a water outlet port (see Fig. 2). The intake-'port 49.ftoV the pump chamber Il Areceives water from thebody' of water in which the propeller and lower hous-- ing structure are submerged through forwardly opening water-intake passages-Ell (see Fig,v 2)..'

The water discharge -or outlet port- 5I) receives water under pressurefrom'the pump Vchamber 4'! and delivers the sameto an'upwardlyopem' ing passagev 52 in the lower-housing'unit 5, which is in communicationlwith andvdelivers'to a wa-` ter delivery pipe' 53`lextending'upwardlythrough the housingstructure :and which maybe lassumed to have its upper delivery end connected housing il and other parts described, a conventional vane rotor 55 mounted fast on a tubular pump shaft 55 (see Fig. 2); The tubular pump shaft 5S is journalled 'at its front end in thev cover plate i8 and has its-rearwardlylprotected end in' telescopic spline keyed engagement with forwardly projected end portion of hub'ZZ journalled within the pump housing li-Xsee'FigrZ). In this manner, the tubular pump shaft 56 :is driven in common with the hub 22 "and the-ene tire housing structure of the` fluidi driveunit and beveled gear 25, and is amplysupported atl-both ends. It is important. to note, by reference par-k ticularly to Fig. 2, that a fluid pressure seal 51 is provided between pump shaft 56 and the bore 5I! of the pump housing 4I; 'and that an O-ring fluid pressure sealf58 is provided inthe annular space between pump shaft 55 and hub 22, whereby BIS the interior of the Water pump lchamber .4l is I5 has an elongated forwardly opening boreY 5I,

which aligns with the bore of thertubular. pump shaft 55 (sie Figs. 2, 3, 7 andl);V` Further, it should be noted, by reference particularly to Fig.

2, that the forwardly projecting end of the bore 5I, and the inner or'front-end of the tubular propeller shaft i5 is spaced from therear end of the tubular water pump shaft 56to provide therebetween a space 62 which'communicateswith the space externally of hub22ithrough a uid dis-'f charge port S3.

Before further describing'the fluid circuit to drive unit or clutchgattention is directed to the following described important features o'f the-in-Y vention, andwhich are, namelya positive-.acting clutch te for positively locking the relatively' amasser rotary pedi-es orenments Aof the nu'idfrzirv unit against-rotation* and avfrictionf-brake55 fseelFi'gI 2) for* *cooperation*4 wi-thffthe AAVVifluid- 'driven' *uniti under conditions of# low torque transfer-` or ihighl slippage to effectively 'increase1thel-- slippage.A ori. decreasei'the actual. rate of f torquetransfer. be-l: tween the-powerhead `I and propeller i4.

The positive-acting mechanicalclutche. comprises-releasably interlockablefdrivingand driven i1 clutch elements respectively indicated by Sand GTi-(see Figli-2). The'saidrdriving clutch elements 66 are in the nature'of y circumferntially-spaced. clutch dogsform'ed-directlyon'ther rear wall 25 of lthe fluid-driven unit-2l v(see Figs.'2, 7 and 8). The" cooperating driveniclutc'h elements El are in the gnature 'of similar fr lcircumferentially-spaced clutch dogs or teeth-'formed on theopposing face of lana axially -shiftable-he'ad 63 (see Fig-.2) and adaptedto-be' brought intorelea'sable int'ermeshingildri'vi'n'g. engagement" witli-A the..cooperating drivingfclutch elernents.v The head VEis annula'rand -is axiallyslidablymountedon the propellerrshaft I5 with-which it hasspline key driving engagement; as indicated lat fand asshown bestlinfFigs. 2 and-3. Atfthis point, and also byi reference particularly-toFigs. .2 and 3, it will beunoted that the .propellershaftl5 is provided between: the spline keys ather-of with an axially elongated slotlll extending diametrically therethrough, fandLthat-the sliding. clutch head 68 carriesrf-a vpin-III, whichfextends .through .Sand worksiiinmthis slot 10.

The :friction .brakea..65 .comprises the shaftcoupled-.'-axially shftable rotary 'head 58 which' serves-"also as -thedriven rotary element of the brake;andy a Lnon-.rotary-friction brake disc l2 (seefFig..2). The friction brake .disc '.'2 is axially slidabilyrmountedon the reduced diameter hub portion-"I3 of-.the he'ad.58;-and. has an annular radially!disposedface forlfrictional engagement with'fa similar opposed faceron the head t3 (see.

Figl2 The-frictionbrak'e-.disc 'I2 is anchored against rotation with'respect` to the Vhousing structure andis yieldingly biased inthe direction oith'elheiadr 58iby means of a tortuous-generally annular spring ring'M anchored to the housingf struo'tu'refatd Vand rto the head -68`at15 (see.v Figl 2) By*referencenowfparticularly to Figs-2, 7 and 8, it vwillbe noted that Vthe'- end wall 25 of the fluid drive unit orA fluid drive slippage clutch 2| is journalled-on the propellershaft lfthrough the med-iumof a sleeve bearing '16',-and that the rotor 3'is provided-with anenlarged-bore portion adjacentits'rear, which provideswithin the rotor and'aboutthe shaft I5 an annular chamber or space'll; which is pressure-sealed by ano-ring seal or packing 718, shown-best-in Figs. 7 and 8. Further important to note in conneotion'with the structuredllustrated is coil compression spring 19,' shown best in Fig. 2, and which has'one end seating. and reacting'against the closed rear end of the' axial'borel of propeller shaft i5, and its other endA seated `and reacting against the pin 'II carried by head 55'; this spring serving to yieldingly urge the head 58 toward a position of interlocking engagement with the rotary outer shell' or housing of fluid drive unit 2l and in which position of the head theifrictionbrake is fullylreleassd.

Next to beldescribed brieflyY will .bethe fluid' ciruitintmthrough, and out ofthe crescentsha'ped chambers t'and S'Iyofithevaria'ble.slip- Pagefluid'drive unit 2iI`.` In this.connectionV it will' i be noted first that thehollo'w tubular portion,"

7 of Lthe propeller shaft 'I5 is provided with a circumferentially-spaced series of radial fluid inlet ports 8B (see particularly Figs. 2, 3, and 7) leading outwardly from its axial bore through mating ports in the sleeve bearing 16', which is fast on and rotates with the propeller shaft I5. Next it should be noted that the propeller shaft I is provided in axially spaced relationship to the series of ports 80 with a similar circumferentially-spaced series of radial ports 8| (see particularly Figs. 2, 3, '1 and 8) leading from the axial bore thereof to the annular chamber or space 11 surrounding the propeller shaft I5 and defined in part by the rotor 3G (see particularly Figs. '1 and 8). The radial propeller shaft ports 8D communicate with a radially inwardly opening circular channel 82 in the rear end wall 25 of the fluid drive unit 2|, as shown clearly in Figs. 2, '1 and 8, which is connected to the diametricallyopposed crescent-shaped chambers 36 and 31 by diametrically-opposed fluid intake passages 83 located in the rear end Wall and shown best in Figs. 2, 5, 6, and 7. Coupling huid is drawn through these passage 83 into the spaces of the crescent-shaped chambers 36 and 31 b-tween circumferentially adjacent vanes 34 or 33 and 34 under relative rotation of the outer shell of the fiuid drive unit and the rotor 3d thereof, and is subject to compression between said adjacent vanes or 33 and 34. When conditions are such as to allow circulation of the fluid through the unit, fluid is discharged under pressure from the crescent-shaped chambers 3B and 31 as follows: The iiuid compressed within the crescentshaped chambers 35 and 31 passes through channels 84 and 35 (see Figs. 6 and 8) in the front end wall 23 of the fluid drive unit and ows generally radially inwardly into circumferentially-extended channels 86 (see Figs. 6, 'l' and 8) in the front face of the rotor 3B from which the fluid flows into the spaces beneath the venes 33. and Sil, from which spaces the fluid is discharged radially inwardly through a circumferentially-spaced series of rotor ports 81 (see Figs. 7 and 8) each leading from a different one. of the several vane-receiving channels 32 of the rotor into the annular chamber 11 (see Figs. 7 and 8) and from thence into the interior bore of propeller shaft I5 through the circumferentiallyspaced series of propeller shaft ports 8| (sae Figs. 7 and 8) when the valve mechanism, later to be described, is in a condition to allow such discharge of fluid from the int-rior of the fluid drive unit. For the purpose of manually controlling the iiow through propeller shaft intake and outlet ports BG and 3|, respectively, I provide a valve plunger or piston 88 axially slidably mounted in the bore of the propeller shaft I5 (see Figs. l, 2, 5, 5, '7 and 8). When this valve 88 is in the position shown in the drawings (see Figs. 2 and '1), fluid is allowed to freely enter the pump-like fluid drive unit through then uncovered propeller shaft ports S (see Figs. 2 and 7) and connected passages, but is not permitted to be discharged from the fluid drive unit, since the propeller shaft outlet passages 8| (see Figs. 2, 7 and S) are now closed. In this position of the valve mechanism, the torque transfer factor of the uid drive unit is at maximum for any given speed. It will be noted that the spaces within the bore of propeller shaft I5 adjacent opposite ends of the valve 88 are connected by ports 89 through said valve 88 (see Fig. '7), so that uid discharged into the bore of the propeller shaft I5 adjacent the front end of valve 88 may pass through the valve into that part of the bore at the rear of the valve 88, which is in communication with the coupling fluid within the cavity I8 through the elongated crank shaft slot 10.

In accordance with the invention, I preferably provide a common control mechanism for the valve 88, positive-acting clutch 64 and friction brake B5. In accordance with the instant illustration, this is accomplished as follows: The valve 88 is integrally formed on the intermediate portion of a push rod 90 (see Figs. 2, 1 and 8) having its rear end abutted against the pin 1I (see Fig. 2) and formed in axially spaced relation to the valve 88 with a guide head 9| (see Figs. 2, 7 and 8). This push rod 90 projects forwardly through and beyond the front e'nd of the propeller shaft I5 and into the tubular pump shaft 56 (see Fig. 2), where it comes into abutting engagement with one end of a short push rod 92 that works axially slidably within the tubular pump shaft 55 and projects forwardly thereof. This short push rod 92 is provided with a packing channel S3 in which is seated an O-ring packing 9d (see Fig. 2), which effectively seals off the coupling fluid-containing cavity I8. The projected front end of the short push rod S2 engages the lower arm of a bell crank S5 (see Figs. l and 2), that is pivoted at 9E to the displaceable element 43 of the housing structure, and works within a cavity 51 in the latter. The upper arm of this bell crank 95 is engaged by the lower end of a long push rod 98 (see Figs. 1 and 2) extending downwardly through and suitably guided in the depending housing structure 4 and 5. The upper end of this long push rod 98 extends upwardly through the upper portion of the housing section d, as shown best at 99 in Fig. 1, where it is connected to a pivoted manually-operated control lever |05. Without going into detail, it will be clear that the push rod 9D is subject to upward and downward movements responsive to arcuate movements of the arcuate control lever IDB, and that with the cooperation of compression spring 19, and bell crank 95, the parts 92, 9D, 88, 68 and 12 will par- A, take of corresponding horizontal movements.

Operation By reference to the drawings, it will be seen that with the parts positioned as illustrated therein, the following conditions prevail, to wit:

(A) The fluid drive unit or slippage clutch is in a condition of maximum torque transfer or minimum slippage due to the fact that valve ports 80 are open to freely admit fluid to the interior of the unit While the fluid discharge ports 8| are closed against discharge of fluid from the fluid drive unit or slippage clutch. It will be understood that even with the parts positioned as shown, the percentage of slippage of the iiuid drive unit will be greatest at the beginning of motion and will automatically decrease as the speed of motion increases.

(B) The positive-acting clutch 54 is in a completely released position so as to allow the relatively rotary elements of the fluid drive unit or slippage clutch to partake otwhatever small degree of slippage may be inherent in the unit, even with the valve element 88 positioned as shown; and

(C) With the parts positioned as shown, the shiftable head 58 is in an intermediate position, wherein the friction brake 65 is just beginning to be applied.

Now, when it is desired to shift the parts so that the power head will idle independently of the `tion of minimum torque transfer.

propeller, the control lever `is moved from its intermediate position,- shown in Fig. l, to an extreme right-hand position with respecttofFig. 1; this pivotal movement of the-'controllever"causing the following functions, towit:

The control rod 98 will be shifted downwardly imparting counterclockwise arcuate movement to bell crank 95, causing acorresponding right-hand shifting movement tov-short push-.rod 92 and long push rod 90, valve headBB, pin 1|, head B8v and brake disc 12, all against the yielding action of compression springs 19, thereby closing fluid intake ports B and opening uid outlet ports 8| of fluid drive unit 2|- andapplying maximum frictional braking pressure to the friction brake 65. It will be understood that with the parts positioned as just described, the fluid drive unit or slippage clutch 2| will be free to exhaust its internal coupling iiuid, while being shut oif vfrom the supply of fluid. Of course, under these conditions, it will be impossibleto build upa fluid driving pressure between the vanes within crescent-shaped chambers or spaces 36 and 31, or, in fact, at any place within the fluid drive unit or slippage clutch 2|, including the spaces within the vane channels 32 beneath the vanes -33 and 34. Hence, the fluid drive unit or slippage clutch will now be in avcon'ditionof maximum slippage drive or, conversely stated, in a condi- However, in spite of this, there will be a slight frictional drag within the fluid drive uni-t 2| tending to impart a slight driving movement tothe propeller |4, but this tendency, which may be referred to as the inherent creep of the fluid clutch, will be overcome by the now set friction brake mechanisin 55, which will hold the propeller stationary. With the parts positioned as `last stated, cranking of the engine will be relatively very easy, since the propeller is idle and will, in itself, produce no resistance to cranking action. `Now if the engine be started with the parts positioned as last-indicated, or in their `extreme right-hand positions with respect to Figs. 1, 2. 7 and 8, the powervhead or engine I, drive shaft I0, bevel gears `|"9 and 2U and the complete outer shell-of the fluid drive unit, including walls 2 3, 25 Yand 26,. -will run together but idle free of the vane-equipped rotor 30, propeller shaft f and propeller |'4. With the power head or engine thus idling or running free, the torque transfer of the 'fluid clutch may be gradually increased Afrom minimumfby gradually Vmoving the control lever |00 in a counterclockwise direction from its extreme right-'hand position, last described, back toward its intermediate position shown, and which movement produces a corresponding right toleft-hand movement of the valve head 88, shif-table head B8 and-clutch disc 12 toward the intermediate position-of the drawings. This movement -may be gradual or by steps and will result in a gradual,progressive, release of the friction brake 65 and a gradual opening of intake ports 8| fand a gradual closing of fluid outlet ports. 8|] to the point where the ports 8| are fully closed and the -ports 80 are fully open andthe friction brake is fully released. During the time t'hat the valve 38 lis positioned so that the ports 8|) Vand 8| fare both partially open, the -ui'd drive unit will function much as a pump l'causing a continuous circulation of coupling fluid therethrough Vunder lthe action of the rotating `vanesyand driving force or torque transmitted to the propeller will vary with various intermediate adjustm'ents4 of the Valve 't3 resulting in varying restriction to fluid` flow through the uid clutch.

V Withvthe unit described, the efficiency of the uid clutch and. the resultant torque transfer factor thereof will lincrease .from the beginning of motion with the vincrease of speed, due to centrifugal action on the vanes 83 and 84, causing the latter tocome into tighter sealing engagement with. the arcuate vinner surfaces of the outer wall 25.. However, it is important to not-e, in connection with the present device, that this-centrifugal action to increase the vsealing characteristics of the rotor vanes 33 and 34, does not come into operation immediately upon starting of the engine, Asince initially power Vis applied by the powerfhead only tothe outer shell of the iuid clutch. Hence, at complete idle and at slow operating speeds, when the rotor 30 is Atraveling much slower than .the power-head driven -outer shell of the unit 2|, leakage past vanes Y33 and 34 will be relatively great due to lack Eof centrifugal sealing action on the vanes, and. the power transfer -factor of the unit will be comparatively very low as compared to what it would-be with the Vane-equipped rotor 3i! positively driven from the lpower head and at a definite speed'with respect thereto. In fact, it is because of this action that it is highly vdesirable to outwardly bias-thevane 33 by the spring 35 in order to insure -sui'licient seal and consequent `fluid pressure internally of 'the unit to insure starting of the rotor. As `the 4pressure within the unit builds up, the vanes 313 and 34 will be forced into tighter and tighter sealing icontact Vwith the inner surface of the wall 26 and` the combined action. of centrifugal force and by increasing fluid -pressure beneath the vanes 33 and 34.

Preferably and with the structure illustrated, the friction brake is graduallyapplied and released coincidentally with the opening and closing of the ports 8D and 8|, but in some cases, `it has been found desirable to slightly alter the structure so that under left to right-hand movements of the valve 88, the ports 8i) will be completely closed -to Vplace the fluid clutchin a condition having mimimum torque transfer factor before beginning to apply the friction brake 65. Of course, this Arevision may be accomplished by the simple expedient of positioning the valve head slightly to the right with respect to Fig. 2, suciently to cover ports 8l), but without changing the axial -positions of the other axially shiftable ports. When this is done, unidirectional movements of the control arm or lever |00 will progressively place the Valve 88 in a position of maximum fluid clutch slippage or minimum torque transfer, and. then progressively apply the friction brake 65.

With the arrangement illustrated, Vthe fluid clutch is utilized for idling of the power vhead or engine and for permitting variable speed of the power head with respect to the propeller for slow speed operation, such as trolling, so as to permit the engine to operate at all times at an eicient speed and well above its stalling speed,

`even though thepropeller may be operated at a very low speed.

However, once the engine or .power head has reached ecient operatingspeed, which may be assumed to be about fifty percent of its maximum speed, the huid clutch will automatically assume a condition 'of very low slippage or'very high torque transfer, so much so that it is then serving no particularly useful function .which cannot more effectively be accomplished by a positive drive. Hence, under these conditions, it becomes desirable to achieve a positive nonslippage drive. With the arrangement illustrated, this is achieved automatically upon progressively moving the control lever 1D0 in a lefthand direction with respect to Fig. 1, to increase the engine speed beyond its mid-range; this action causing a left-hand shifting o f the head 68 to an extreme left-hand posiiton, not shown, but causing positive engagement of the cooperating elements 66 and 61 of the positive-acting clutch 54 and consequent locking of the relatively rotary elements of the fluid slippage clutch against further relative rotation.

It will be understood that fluid coupling units or slippage clutches, generally, essentially generate heat under conditions of torque transfer, and thereby presents a cooling problem. It will be seen that in the arrangement illustrated, the

heat generated in the fluid coupling unit or clutch 2l will be transferred to the coupling fluid surrounding the said unit and will be passed from thence through the surrounding housing structure to the water in which the propeller is submerged. Otherwise stated, the same coupling fluid, being oil, is utilized for three purposes, namely:

(1) As a coupling fluid;

(2) As a heat transfer medium; and

(3) As a lubricant for the mechanical elements of the structure.

What I claim is:

l. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion dening a cavity, a fluid coupling unit contained within said cavity, said cavity providing a fluid reservoir space adjacent the fluid coupling unit, said fluid coupling unit comprising relatively rotary members and a fluid space therebetween that is in communication with the reservoir space adjacent the coupling unit, power transmission means between one of the said relatively rotary members of the fluid coupling unit and the power head, a propeller shaft journalled in the normally submerged portion of the housing structure with its inner end portion extending into said cavity and coupled to the other of said relatively rotary members of the fluid coupling unit, and a coupling iluid within the iluid reservoir portion of said cavity, whereby heat generated in the fluid coupling unit will be rapidly dissipated to the water in which the housing structure is submerged through the said coupling fluid and housing structure.

2. In an outboard marine motor, a power head. housing structure depending from the power head and including a normally submerged portion, the normally submerged portion of the housing structure defining a fluid reservoir and atransmission mechanism chamber, a fluid coupling unit contained within said chamber; said unit comprising relatively rotary inner and outer fluid coupled body members, the last said member providing a casing for the first said member and a coupling fluid and the interior thereof being in fluid exchange relationship with the submerged fluid reservoir; coupling fluid within the outer fluid coupled member and said reservoir, a driving connection between the power head and one of said fluid coupled body members, a propeller shaft journalled in the submerged portion of said housing structure-with its inner end coupled to the other fluid coupled member,

and a' propeller mounted on the outer end of said'propeller sha-ft,Y heat generated in the uid coupling unit being carried by the driving fluid to the submerged fluid reservoir of the housing structure and being radiated through the latter directly to the water in which the reservoir portion vof the housing structure is submerged.

3. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a fluid coupling unit contained within the lower part of the normally submerged portion of the housing structure, the said submerged portion of the housing structure defining communicating fluid reservoir spaces immediately adjacent the opposite sides of said fluid coupling unit, said lluid coupling unit comprising relatively rotary members and a coupling fluid space therebetween that is in communication with the said reservoir spaces, a coupling fluid in the space between the relatively rotary members 'of the fluid coupling unit and within the reservoir spaces adjacent said unit, power transmission means between one of said relatively rotary members of the coupling unit and the power head, a propeller shaft journalled in the lower part of the normally submerged portion of the housing structure with its inner end coupled to the other of the relatively rotary members of the coupling unit, and a propeller mounted on the propeller shaft externally of the housing structure, whereby heat generated in the fluid coupling unit will be rapidly dissipated to the water in which the housing structure is submerged through said fluid and housing I" structure.

4. The structure deried in claim 3 in which the normally submerged portion of the housing structure also defines a relatively large coupling fluid reservoir chamber above and in communication with the reservoir spaces immediately adjacent the coupling unit, and which serves to further facilitate the rapid transfer of heat from the coupling unit tothe Water in which the housing structure is submerged.

5. The structure deiined in claim 3 in which the normally submerged portion of the housing structure also defines a relatively large coupling fluid reservoir chamber above and in communicaton with the reservoir spaces immediately adjacent the coupling unit, and which serves to further facilitate the rapid transfer of heat from the coupling unit to the Water in which the housing structure is submerged, the last said fluid reservoir extending upwardly substantially to the plane of the top of a circle described by the outer peripheral portion of the propeller.

6. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a

propeller shaft journalled in and projecting through a wall of the normally submerged portion of the housing structure, a propeller mounted on the outer end of the propeller shaft, driving connections extending through the housing structure from the power head to the propeller shaft and comprising a variable torque transfer .slippage clutch, a friction brake within the housing structure between the clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the variable torque transfer slippage clutch and a cooperating nonrotary friction element, and control mechanism for said variable slippage clutch and said friction brake, said control mechanism comprising a common manually shiitable control element to SiS-423582 I3 which said meohanis'mis responsive tofcoineidentally and progressively reduce the torque transfer factor of the slippage clutch and app-1yr' the friction brake.

v7. In an outboard motor, apower head-housing structure depending from the power head and including a normally submerged por-tion, a pro-- peller Ashaft journalledin and f proj ecting through a wall of the-normally Ysubmerged 'portion of the housing structure, 'a propeller mounted on the outer end'of the propeller shaft, driving connection-s extending through the housing structure from the power'head to the propeller shaft and comprising a variable torque transfer slippage clutch, a friction brake withinthe housing structurebetween the clutch and propeller shaft, said 'friction brake comprising a'rotary friction element ldriven by the variable torque transfer slip- 'page clutch Aand a cooperating non-rotary friction yelement, and control -mechanism for 'said variable slippage clutch and'said friction brake, said 'control mechanism comprising a 'common manually s'hiftable control element to unidirectional movements of whichsaid mechanism is vresponsive to progressively reduce "the torque transfer factor of the slippage clutch and progressively apply the frictionbrake.

8. In an outboard motor, a power head'housing structure depending from'the power head and including a normally 'submerged portion, fa lpropeller shaft journalled in and projectngthrough a wall of the normally submerged portion ofthe housing structure, a propeller mounted on the outer fend of the `propeller shaft, driving connections extending through the housing 'structure from the power head to the 'propeller shaft and comprising a variable slippage uid clutch mechanism said fluid clutch n'iecha'nism'y involving a shiftable 'element for' regulating the torque transfer factor of the fluid clutch, a Vfriction brake within the housing structure between .the clutch and propeller shaft, lsaid friction brake comprising a rotary friction Aelement driven by the fluid clutch `and a cooperating 'non-rotary friction element, and control mechanism for' the shiftable regulating element of the fluid clutch and the friction brake, said "control nmechanism comprising a common manually shiftable control element to which said mechanism is responsive to coincidentally 'and vprogressively :reduce :the

torque `transfer factor of the fluid clutchv and apply the friction brake.

9. In an outboard motor, a power head', .housing structure dependingfrom the power head-and including a normally submerged portion, aspropeller shaft journalled in andprojectingthrough a wall of the normally submerged portionof the housing structure, a propeller mounted on the outer end of the propeller shaft, driving connectionsA extending through the housingstructure from kthe power head to the propeller shaft and comprising a variableslippage fluid clutch mechanism, said, fluid clutch mechanism comprising a shiftable valve element for regulating the torque transfer factor of the fluid clutch, l.a friction brake within the housing structure between the clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the fluid clutch mechanism, and a cooperating non-rotary friction. element, .and control mech- .anism for said shiftable valve element .and the friction brake, said control mechanism comprising a common manually shiftable controlelemen-t to which said mechanism is responsive to coincidentally and progressive .move theshiftable :clutch mechanism, .said uid clutch mechanism comprising a shiftable valve element for `regulating the `torque .transfer factor Vof the fluid clutch, a friction bralrewithin the housing structure `between 'theclutch and propeller shaft, said friction brake 'comprising .a rotary friction element'driven by the fluid -clutch mechanism, and a .'co'operating.v non-rotary friction element, and control mechanism for said shiftable Vvalve'element and the friction brake, lsaid controlimechvanisrh lcomprising a single-manually operable `control element' to unidirectional movements of which saidmechanism is responsive toprogresvsively `move the 'shiftable valve element toward a V.position of minimum `torque transfer .and to Yprogressively apply the :friction brake.

11. Inan .outboard motor, apowerhead, housing structure depending from the powerhead and including .a normally submerged portion, a propeller'shaft journalled in and vprojecting through Y a wall of the'normally submerged portion of the housing structure, a propeller mounted on the outer end iof the propeller shaft, driving connections extending through the housing `structure from the 4power head to the propellershaft;

lsaid. driving connections comprising a variable torque transfer slippage clutch, and a releasable positive acting clutch forpositively locking the vvariable torque transfer slippage clutch against slippage; a friction brake within the housing structure between 'the `positive acting clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the variable torque transferslippage clutch and a cooperating non-rotary friction element, and control mechanism for the variable torque transfer slippage' clutch, positive-acting clutch means and friction-brake, said control mechanism comprisling Ya common manually shiftable control lelement to which said mechanism. is responsive to -rst .release the positive-acting'clutch and then coincidentally and progressively reduce Ythe torque transfer factor-of the slippage clutch and applythe friction brake. t

.'12. In an outboard motor, a power head, housving structurev depending from the power head and including .a normally submerged portion, a propeller shaft journalled in and projecting through awallof the 4normally submerged por- -tion 'of the' housing structure, a propeller mounted on-the outer end of-'the propeller shaft, driving connections extending through the housi-ngfstructure `from tl1e-power rhead to the propeller 'shaftj .said driving' connections compris- -ng .a variable torque transfer slippage clutch, .anda releasable positive acting clutch for positively locking the variable torque vtransfer slippage vclutch against slippage; a friction brake withinnthe housing structure between the positive acting-clutch 'and propellershaft, said fricftion brake comprising a rotary friction element driven by the variable torque transfer slippage `clutch and a cooperating .non-rotary Vfriction -tion of the housing structure.

element, and control mechanism for the variable torque transfer slippage clutch, positive-acting clutch means and friction brake, said control mechanism comprising a common manually shiftable control element to progressive unidirectional movements of which said mechanism isv responsive to first release the positive acting clutch and then progressively reduce the torque transfer factor of the slippage clutch and progressively apply the friction brake.

13. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a propeller shaft journalled in and projecting through a wall of the normally submerged portion of the housing structure, a propeller mounted on the outer end of the propeller shaft, driving connections extending through the housing structure from the power head to the propeller shaft and comprising a variable slippage fluid clutch mechanism, said fluid clutch mechanism involving a shiftable element for regulating the torque transfer factor of the fluid clutch, a releasable positive-acting clutch for releasably locking the fluid clutch against slippage, a friction brake within the housing structure between the clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the fluid clutch and a cooperating non-rotary friction element, and control mechanism for the shiftable regulating element of the fluid clutch and friction brakeand positive-acting clutch, said'control mechanism comprising a common manually shiftable control element to which said mechanism is responsive to rst release the positive-acting clutch and then coincidentally and progressively reduce the torque transfer factor of the fluid clutch and apply the friction brake.

14. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a propeller shaft journalled in and projecting through a wall of the normally submerged portion of the housing structure, a propeller mounted on the outer end of the propeller shaft, driving connections extending through the housing structure from the power head to the propeller shaft and comprising a variable slippage fluid clutch mechanism, said fluid clutch mecha- -nism comprising a shiftable valve element for regulating the torque transfer factor of the fluid clutch, a releasable positive-acting clutch for postively locking the variable slippage fluid clutch mechanism against slippage, a friction brake within the housing structure between the clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the fluid clutch mechanism and a cooperating non-rotary friction element, and control mechanism for said valve element, positiveacting clutch and friction brake, said control mechanism comprising a common manually shiftable control element to which said mechanism is responsive to first release the positiveacting clutch and then coincidentally and progressively move the shiftable valve element toward a position of minimum torque transfer and to apply the friction brake.

15. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a propeller shaft journalled in and projecting through a wall of the normally Asubmerged poraV propeller mounted on the outer end of the propeller shaft, driving connections extending through the housing structure from the power head to the propeller shaft and comprising a variable slippage fluid clutch mechanism, said fluid clutch mechanism comprising a shiftable valve element for regulating the torque transfer factor of the fluid clutch, a releasable positive-acting clutch for positively locking vthe variable slippage fluid clutch mechanism against slippage, a friction brake within the housing structure between the clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the fluid clutch mechanism and a cooperating non-rotary friction element, and control mechanism for said valve element, positive-acting clutch and friction brake, said control mechanism comprising a common manually shiftable control element to which said mechanism is responsive to rst release the positive-acting clutch and then progressively move the shiftable valve element toward a position of minimum torque transfer and to progressively apply the friction brake.

16. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a propeller shaft journalled in and projecting through a wall of the normally submerged portion of the housing structure, a propeller mounted on the outer end of the propeller shaft, driving connections extendingv through the housing structure from the power head to the propeller shaft, said driving connections comprising a variable slippage fluid clutch, shiftable valve means for controlling the slippage of the fluid clutch, a friction brake within the housing structure between the fluid clutch and propeller shaft, said friction brake comprising a rotary friction element driven by the fluid clutch and a cooperating non-rotary friction element, and operating mechanism for said valve means and said brake which includes a common manually shiftable control element to which said mechanism is responsive to successively shift the valve means to a position of'maximum fluid clutch slippage and to apply the friction brake.

17. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion defining a cavity, a fluid clutch contained within said cavity, said cavity providing a fluid reservoir space adjacent the fluid clutch, said fluid clutch comprising relatively rotary members and a space therebetween that is in communication with the reservoir space adjacent the fluid clutch, power transmission means between one of the relatively rotary members of the fluid clutch and the power head, a propeller shaft journalled in a wall of the normally submerged portion of the housing structure with its inner end portion eX- tending into the coupling fluid reservoir space of said cavity and coupled to the other of the relatively rotary members of the fluid clutch; a coupling fluid within the coupling fluid reservoir space of said cavity, a friction brake within said coupling fluid reservoir space between the fluid clutch and propeller shaft, said friction brake being submerged within the coupling liquid in the reservoir portion of said cavity and comprising a rotary friction element driven by the fluid clutch and a cooperating non-rotary friction ele-- ment mechanism for applying and releasing the friction brake, heat generated in the fluid clutch and friction brake being rapidly dissipated to'the nwater in `which 'the housing :structure'vfisprsubmerged -th-rough said :coupling 4iluid and housing structure.

118. `The structure vdefined in fclaim'lfl vinifurthe combination :with a "mechanical clutch releasably s;

tlocking the `relatively -rotary members of the iiuid lclutch vagainst relative rotation, said mechanical 19. In anoutboard motor, a power head. heusk "ing structure depending from fthe power I"head and including a normally submerged portion defining a cavity, a fluid clutch 'contained within said cavity, -said Vcav-ity providing a ifluidlreservoir lspace adjacent the fluid clutch, -said fluid clutch comprising relatively rotary members and a space therebetween that vis 1in `communication with :the reservoir space adjacent the iluidA clutch, power transmission means vbetween one of -the relatively Vrotary members of the -fl-uid clutch and the power head, -a propellershaft journalled in a wall fof the normally submerged portion ofthe housing str-ucturewith its inner end portion extending into the coupling uid reservoir space of, said cavity and coupled to the'o'ther `of the relatively rotary members of the iiuid clutch, na `coupling ifluid l-,within the coupling fluid reservoir space of :said-oavity, a mechanical clutch .contained within the uid reservoir space o'fsa'id cavity 'for releasably locking the relatively rotary members of the fluid clutch against vrelative rotation, a releasablefriction brake also located within the coupling fluid reservoir space of the cavity between the iiuid clutch and propeller shaft, said mechanical clutch and friction brake being submerged within the coupling liquid in the reservoir portion of the cavity and comprising a rotary friction element driven by the uid clutch and a cooperating nonrotary friction element, and mechanism for applying and releasing the mechanical clutch and l applying and releasing the friction brake, said mechanism comprising a single manually-operated control element responsive to which rsaid mechanism is responsive to successively release the mechanical clutch and set the friction brake, heat generated in the fluid clutch and friction brake being rapidly dissipated to the water in which the housing structure is submerged through said coupling liquid and housing structure.

2D. In an outboard motor, a power head, housing structure depending from the power head and including a, normally submerged portion defining a cavity, a iluid clutch contained within said cavity and comprising a casing-acting shell journalled for rotation within said cavity, and a rotor journalled within said casing-acting shell and coupled thereto by an interposed fluid-driving medium, a propeller shaft journalled in and projecting through the normally submerged wall portion of the housing structure and coupled to the rotor of the fluid clutch, mechanical driving connections extending through said housing structure to the shell-like casing oi the fluid clutch and positively driving the latter, a releasable mechanical clutch interposed between the shell and rotor of the fluid clutch, a releasable friction brake interposed between the propeller shaft and housing structure, said mechanical clutch and friction brake also located within said cavity, and mechanism for operating the mechanical clutch and friction brake, the last-said mechanism comprising a single manually-operated control element responsive to a unidirectional movement of which the said mechanism will iirst vrelease :the-:mechanical -clutchand -thenfpnogres- 'fsivelyiapplythe.frictionbrake.

21. In :an outboard motor, *.a power head, ihousing structure vdepending from .the Ypower head and including a normally submerged portion fdc- :lining 'a cavity, a variabile slippage -fluid clutch contained within the :cavity and compris- Jing relatively rotary inner :and outer iluid Vcoupled bodies, "a lpropeller shaft journalled in 'and projecting through a wall olf lthe normally submerged portion of the :housingfstructure coupled to Aone Yof the relatively rotary bodies vof the variable slippage .uid clutch, 'mechanic al ydriving connections extending through the housing structure lfrom the power head .to the other relatively rotary body of the fluid clutch and positively driving the latterfvalve .means xcontrolling ".the slippage ofthe fluid clutch and comprising a 'valve element fmounted `Vfor shifting movements between positions :of minirmum and maximum 'ilu'id clutch slippage, a ireleasable mechanical clutch for positively vlock-k ing the relatively rotarylbodies ofthe duid-*clutch `against relative rotation Iand comprising Irelatively shiftalble cooperating clutch elements-:each

mounted ffor rotation with La diifere'nt one-'of the relatively rotary-"bodies of the fluid clutch,1a re- -leasable ifric'tion .brake `interposed betweenfthc prope'ller shfaft coupled body of the fluid fclutch Vand the housing structure, said valve element, y 'imeohanical :clutch :and lfriction :brake b'eingfalso located :lin the 'said Acavity foi the normally'isubmerged portion of the housing structure, and mechanism for operating the valve element, mechanical clutch and friction brake, the last said mechanism comprising a single manually operable control element responsive to unidirectional movement of which the said mechanism will successively release the mechanical clutch, shift the valve of said valve element to a position of maximum clutch slippage, and progressiVely set the friction brake.

22. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion, a propeller journalled in the submerged portion of the housing structure, a variable slippage fluid clutch mounted in said housing structure intermediate the power head and propeller shaft, said variable slippage uid clutch comprising a journalled rotary shell defining a pump chamber, a rotor working within said pump chamber and journalled in said rotary shell for rotation with respect thereto, said moto-r having a circumferentialy-spaced loutwardly-opening generally radially disposed vane channel in its peripheral portion, anda vane slidably mounted in said vane channel and responsive to centrifugal action resulting from rotor rotation to make varying degrees of sealing engagement with the inner peripheral surface of the shell increasing with the speed of rotation of the rotor, a source of coupling uid in communication with said pumping chamber, means positively driving the I .rotary shell of the iluid clutch from the power )and including a normally submerged portion, a

propeller journalled in the submerged portion of the housing structure, a variable slippage fluid clutch mounted in said housing structure intermediate the power head and propeller shaft, said variable slippage uid clutch comprising a journalled rotary shell defining a pump chamber,

a rotor working within said pump chamber and journalled in said rotary shell for rotation with .respect thereto, said rotor having circumferentially-spaced outwardly-opening generally radially disposed vane channels in its peripheral portion, and vanes slidably mounted in said vane channels and responsive to centrifugal action resulting from rotor rotation to make Varying degrecs of sealing engagement with the inner peripheral surface of the shell increasing with the speed of rotation of the rotor, a source cf coupling fluid in communication with said pumping chamber, means positively driving the rotary shell of the uid clutch from the power head, and means positively driving the propeller from the iiuid clutch rotor.

24. The structure defined in claim 23 in further combination with a spring yieldingly biasing one of the rotor vanes outwardly in the direction of the cooperating inner peripheral surface of the shell, whereby to assure the establishment of a suillcient fluid seal between said vane and the shell in astatic condition of the rotor, the other vanes being dependent solely upon centrifugal action to maintain sealing engagement with th inner peripheral surface of the shell.

25. In an outboard motor, a power head, housing structure depending from the power head and including a normally submerged portion dening a cavity, a variable slippage uid clutch contained within said cavity, said uid clutch comprising a. rotary shell journalled in the housing structure and dening a pump chamber, and a uid coupled rotor working in the pump chamberjand journalled to the rotary shell for independent rotation, a. propeller shaft positively coupled to the pump rotor and extending therefrom through and journalled in a wall of the submerged pcrtion of the housing structure, a propeller on the outer end of said propeller shaft, a power head driven drive shaft extending downwardly through the housing structure into said cavity, a beveled gear fast on the lower end of said drive shaft, and an intermeshing beveled gear fast on the shell of the fluid clutch.

26. The structure deined in claim 25 in which said cavity provides a driving fluid reservoir space largely surrounding the fluid clutch and beveled gears, a coupling liquid in said reservoir space to a level above said fluid clutch and gears, and passages providing communication between the pumping chamber of the uid clutch and said uid reservoir space.

DALE D. KLOSS.

REFERENCES CITED UNITED STATES PATENTS Name Date Hillborn July 5, 1927 Number 

